<video id="demo" width=720 height=300 controls>
    <source src="video.mp4" type="video/mp4">
    Video not supported by your browser.
</video>

var v = document.querySelector('#hero-video');
​
// PAUSE
v.addEventListener('pause', function() {
    UST.addTag('video_paused');
    // You can also add another tag with the exact time at which the video was paused
    UST.addTag('video_paused_at_' + Math.round(v.currentTime));
});
​
// PLAY
v.addEventListener('play', function() {
    UST.addTag('video_play');
});
​
// ENDED
v.addEventListener('ended', function() {
    UST.addTag('video_end');
});

// Add a tag for users who scroll at least once on the homepage
window.addEventListener('scroll', function didScroll() {
    UST.addTag('scrolled_on_home');
    window.removeEventListener('scroll', didScroll); // Sending it once is enough, remove listener
});